What is "main deck"

main deck \main deck\ n. The uppermost sheltered deck that runs the entire length of a large vessel.

Syn: second deck.

n. the uppermost sheltered deck that runs the entire length of a large vessel [syn: second deck]

The main deck of a ship is the uppermost complete deck extending from bow to stern. A steel ship's hull may be considered a structural beam with the main deck forming the upper flange of a box girder and the keel forming the lower strength member. The main deck may act as a tension member when the ship is supported by a single wave amidships, or as a compression member when the ship is supported between waves forward and aft.